The invention relates to a flexible duct for use in microturbine systems.
The present invention provides a flexible duct adapted to be secured to first and second components of a thermodynamic system. The duct has a first duct section with an intake end, an exhaust end, and a central axis. A duct-intake plane is defined by the intake end, and a first joint pivotally couples the intake end to the first component. A second duct section has a first end and a second end, and a second joint pivotally couples the first end to the exhaust end of the first duct section. A third joint pivotally couples the second end to the second component.
The first joint permits pivotal movement about a first axis that is generally parallel to the duct-intake plane. The second joint permits pivoting of the first and second sections with respect to each other about a second axis that is generally parallel to the first axis. The third joint permits the second section to pivot with respect to the second component about a third axis that is generally perpendicular to the first axis. The duct is thus configured to provide a substantially air-tight conduit for fluid flow between the first and second components of the thermodynamic system.
The first joint may include a plate that is mounted to the first component, and a pair of pivot tabs that depend generally perpendicularly away from the plate. The tabs may also be generally parallel to, and on opposite sides of, the central axis, such that the first axis extends through both the pivot tabs and the central axis. The pivot tabs may each include a rounded distal end, and the intake end may include a flange. Preferably, the flange has recesses that are configured to receive the distal ends of the pivot tabs to provide pivotal movement of the first duct section with respect to the first component about the first axis. More specifically, the intake end rocks on the distal ends of the pivot tabs.
The first duct section may further include a circumferential groove surrounding the intake end, and the duct may further include a resilient O-ring. Preferably, the O-ring is retained within the groove and engages the first component to provide a substantially air-tight seal between the first component and the first duct section.
The second joint may include first and second mounting members that are affixed at diametrically-opposed positions on the exhaust end of the first duct section; similarly, third and fourth mounting members may be affixed at diametrically opposed positions on the first end of the second duct section. Preferably, the third and fourth mounting members are aligned with the first and second mounting members respectively. The second joint may also include a first tie rod that couples the first and third mounting members and a second tie rod that couples the second and fourth mounting members. The tie rods are preferably substantially parallel to each other. The second joint preferably enables relative pivotal movement between the exhaust end and the first end about the second axis, and the second axis is preferably generally perpendicular to the first and second tie rods.
The first end of the second duct section may include an expanded portion, and the exhaust end may be inserted into the expanded portion. The flexible duct may also include an additional resilient O-ring that snugly engages the first end and the exhaust end to maintain an air-tight seal between the first and second duct sections as the first and second duct sections pivot with respect to each other. Preferably, a circumferential groove surrounds the exhaust end and faces generally away from the central axis such that the O-ring may be retained within the circumferential groove.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.